基于FRAP的微间隙润滑油膜流速测量方法

Velocity profile measurement of oil films in a confined gap based on FRAP

薄油膜润滑广泛存在于各类精密机械与微机电系统中。微纳米间隙内的润滑油流动是影响薄膜润滑承载力的重要因素,但目前薄润滑油膜的流速测量仍然缺少有效手段。本文基于荧光漂白恢复显微技术和漂白区域形状演化过程的成像分析,建立了油膜流速测量系统,可以对微米间隙润滑油膜的速度分布进行原位测量。利用建立的系统获得了厚度为8μm时聚丁烯PB450润滑油膜的库埃特流速分布。重建的荧光漂白强度分布曲线和实验测量结果的皮尔森相关系数大于0.95,且流速分布符合已有润滑理论,证明了测量结果的可靠性。

The flow of lubricant oil films in confined gaps of micro-scale is a significant factor to affect load-carrying capacity of lubrication films in precision machines and micro-electro-mechanical systems （MEMS）.In order to research the lubricating property of thin lubricant film the paper established through-thickness velocity profile measurement system and carried out a on-line situ measurement on through-thickness velocity profile of thin oil film under confined micro-gaps,based on fluorescence recovery after photobleaching （FRAP） and imaging analysis of shape changes process in the bleached area.The method adopted an assumption that the fluorescence intensity is distributed and layered along the film thickness direction,combined two-dimensional bleaching ability distribution information varying with time to acquire velocity distribution of the film thickness direction and the velocity profile of a 8 μm thickness of PB450 polybutene lubricant film.Pearson correlation coefficient of the experiment result and reconstructed fluorescent agent intensity distribution curve is greater than 0.95 and the velocity profile conforms to existing lubrication theory,which proves the reliability of the measuring results.